Flood prediction and design calculation in ungauged region are often restricted by data of rainfall and runoff. Based on the DEM data extraction of Horton geomorphologic parameters in Luoyang river basin, geomorphic units line of Luoyang river was calculated, and the basin confluence and the response relation between geomorphic parameters was established. The three layers of evaporation and saturation excess runoff were used to construct Xin’anjiang model based on geomorphic unit line. Luoyang river basin flood simulation was carried out by combination of genetic algorithm with objective optimization. Compared with Xin 'anjiang model, the results show that the Xin’anjiang model based on geomorphic unit line can obtain better simulation results, which can provide reliable technical support for hydrologic analysis and calculation of small and medium-sized rivers in ungauged region.

A CVMD-GRU-DenseNet model for short-term load forecasting based on a decomposition-prediction-reconstruction framework is proposed to aim at the nonlinear and multi-period characteristics of power load time series. In the decomposition stage, the optimal decomposition number of VMD is determined according to the correlation entropy between subsequences to improve the decomposition quality. In the prediction stage, the input features are selected according to the characteristics of each sub-sequence. The GRU neural network and the DenseNet model are employed to forecast the regular low-frequency and highly random high-frequency components, respectively. Finally, the prediction results for each element are reconstructed into a load prediction curve. The short-term load forecasting results of four seasons for a city in Hubei Province show that the proposed method can effectively improve forecasting accuracy and has strong generalization ability.

The problem of waterlogging in old city has become the focus of natural disaster research. Taking Fenghuang District of Nanchang City as an example, the MIKE FLOOD model was established to analyze the risk and causes of waterlogging. Based on the above results, the SWMM model was used to conduct the research on LID layout and optimization. Analytic hierarchy process was used to evaluate its comprehensive benefits, and the optimal cost-benefit scheme was finally obtained. According to the study, the rainfall return period is 5 years, there are 16 waterlogging points, and the risk level of waterlogging in some areas has reached level Ⅳ. It can be seen that the urban waterlogging prevention and control research is urgent. LID combination facilities have a good effect on alleviating waterlogging. The scheme of 22.5% rainwater garden +7.5% pervious pavement is the best. This conclusion can provide technical reference for the following low impact development and construction of sponge cities and the proportion selection of facilities.

In view of the uncertain factors of natural inflow and electricity price during participating in bilateral transactions at different time scales for cascade hydropower plants, there are problems of market share determination, water resources utilization and profit risk since electricity allocated irrationally. Therefore, this paper presented a risk-based optimal combination model of medium- and long-term contract electricity for cascade hydropower stations. To realize the goal of the minimum profit risk under a given confidence, the monthly inflow process was randomly generated by annual inflow data. Three electricity price functions were fitted by different proportions of hydropower stations in the market. The combination of power output and contract electricity of cascade hydropower plants were solved by the loop-Iteration method of hybrid progressive optimization with successive approximation method. The model was demonstrated using the hydropower plants in the southwest region. The results show that proposed model can determine the declaration strategy between monthly and annual bilateral contract electricity, and reduce the profit risk. It can provide reliable basis for bilateral transactions at different time scales of cascade hydropower plants.

The large pulses superimposed on the upper guide swing time-domain waveform measured by the eddy current displacement sensor of a generator-motor in a certain pumped storage station which affects the accuracy of the post-data processing. The data measured were analyzed in detail, and a three-dimensional finite element simulation model was established for calculation and verification. It is concluded that the fixed mode of the magnetic pole lead of the generator-motor on the upper end shaft is the main cause of large pulse. The temporary measures and completely improvement measures to ensure the accuracy of data were proposed, which are he pulse data elimination method and the sensor replacement method, respectively. It can provide the reference for the accurate measurement of the upper guide swing of a generator-motor with the same type of shaft-through mode.

In order to study the correlation and distribution characteristics of arsenic (As 75) and other trace elements in the water of plateau rivers, the trace elements in the water of Yalong River in July 2021 (wet season) and November 2021 (dry season), an important tributary of the Yarlung Zangbo River, were investigated and analyzed. Based on correlation analysis, cluster analysis and principal component analysis, the relationships among arsenic 75 (As 75), boron 11 (B 11), iron (Fe 57), strontium 88 (Sr 88), tin 118 (Sn 118), lithium 7 (Li 7), vanadium 51 (V 51), cobalt 59 (Co 59), nickel 60 (Ni 60), copper 63 (Cu 63), zinc 66 (Zn 66), selenium 82 (Se 82), molybdenum 98 (Mo 98) and lead 208 (Pb 208) in water were explored. The results show that there are significant differences among the elements in wet season and dry season, which can be divided into three categories: The elements with stable contents in wet season and dry season (Ni 60, Co 59, Cu 63, Li 7, Zn 66); The elements with obvious seasonal variation (Sr 88, V 51, Mo 98, Li 7, Se 82, As 75, B 11, Pb 208); Elements less associated with other elements (Sn 118). In addition, most of the trace elements in the Yalong River Basin are related to Ni 60, Co 59, Cu 63, Li 7 and Zn 66. The study can provide scientific basis for understanding the changes of water environment in the basin and subsequent environmental protection.

Plain river network, especially near the airport area, has complex hydrological structure, and the flood control and drainage are very important. Taking the Hangzhou International Airport as an example, one-dimensional hydrodynamic model of the river network was built based on MIKE11. The current situation of drainage was analyzed through different startup conditions of the existing drainage pumping station, and the optimization and promotion plan was proposed. The result indicates that the overall drainage capacity of the West Work Area of Hangzhou Airport cannot meet the standard of “once in 20 years”, which needs to be optimized for drainage. Under comprehensive consideration, it is recommended to use strong drainage instead of regulation and storage, and adopt the drainage idea of "mainly strong drainage, combined with regulation and storage" to form an overall drainage pattern of "backbone river channel + strong drainage pumping station".

The tidal river network area has the characteristics of criss-crossed water systems and developed cities. High intensity land use and development leads to serious hydrological pollution and degradation of ecological environment functions of urban landscape lakes. Taking the typical urban landscape lake in the river network area - Baiyun Lake in Guangzhou as the research object, this paper constructed a two-dimensional hydrodynamic and water quality coupling model to study its eco-environmental water demand and its water supplement schemes. The results show that the two-dimensional hydrodynamic and water quality coupling model in the river network area based on Mike21 can effectively simulate the temporal and spatial evolution law of water quality in urban landscape lakes, and the relative errors between the simulated values and the measured values are less than 0.20, Nash efficiency coefficients are greater than 0.75. By jointly using Baiyun Lake sluice and pump hydraulic engineering to dispatch and replenish water, the assurance rates of eco-environmental water demand of Baiyun Lake and its connected rivers are basically 100%, the contents of TN and TP meet the fourth class water quality. The research results can provide reference for ecological and environmental governance of urban landscape lake of polluted river network.

Dewatering in deep well would lead to the decline of groundwater level and reduce the strength and stability of the soil, which affects the construction safety of the diversion tunnel. In order to study the influence of deep well dewatering on the seepage field of the tunnel during the construction period, a three-dimensional seepage finite element model of Chuanqin tunnel of Xixiayuan water control project and irrigation area project was established. The construction plan of the tunnel and the change of Qinhe water level were considered to analyze the seepage characteristics of the tunnel under the conditions of deep well dewatering and without dewatering. The results show that the dewatering of the deep wells affects the tunnel excavation, changes the potential distribution characteristics of the seepage field around the deep well, forms a falling funnel on the infiltration surface. The water level contour is in a backwater ring near the deep wells. Compared with the deep well without dewatering, the maximum seepage gradient and unit width seepage flow of deep well dewatering are increased by 18.6 times and 3.3 times, respectively, and the seepage stability of soil layer under all working conditions meets the requirements. The research results can provide a basis for the design and construction of similar water diversion projects.